It is somewhat tempting to call this German-based group a direct rip-off of early Enigma, but that would be unfair. While Enigma's influence is clearly present, the songwriting and arrangement of producer Alex Wende have a distinct and powerful sound. Thomas Pflanz contributes Latin lyrics, which are sung by an all-male choir on the first two albums, and a mixed choir on the third. Though frequently reminescent of Gregorian Chant, the choirs' performances are not strictly limited to this style. LesiŽm's albums are also characterized by a great variety of solists and strong but subtle synths and bass lines.
In addition to LesiŽm's official website, you may find this Russian fansite useful.
Note: LesiŽm's albums are released by different labels, with different titles and packaging on different sides of the Atlantic. Living in Texas, I refer to the American releases.